Hydraulic control valve for machine tools



w. s. BUNNELL 2,851,996

HYDRAULIC CONTROL VALVE 'FOR MACHINE TOOLS Filed May 18, 1955 4 Sheets-Sheet 1 Sept. 16,1958

jg. 3 I EZEJTZEE' WILLIAM S. BUNNELL Sept. 16, 1958 w. s. BUNNELL 2,851,996

HYDRAULIC CONTROL VALVE FOR MACHINE TOOLS Filed May 18, 1955 4 Sheets-Sheet 2 igJz [ CAPE/AGE M0702 CYL/A/DEE &'

WILLIAM S. BUNNELL Sept. 16, 1958 w. s. BUNNELL' HYDRAULIC CONTROL VALVE FOR MACHINE TOOLS 4 Sheets-Sheet 3 Filed May 18, 1955 .JZEZEIETE: WILLIAM S. BUNNELL N x 3. k

' w. s. BUNNELL 2,851,996

HYDRAULIC CONTROL VALVE FOR MACHINE TOOLS 4 Sheets-Sheet 4 Sept. 16, 1958 Filed May 18, 1955 a Q *3 x n R w: a

i R I I t\ m RE WILLIAM S. BUNNELL United States Patent HYDRAULIC CONTROL VALVE FOR MACHINE TOOLS William S. Bnnnell, La Grange Park, 111., assignor to Boyer-Schultz Corporation, Br'oadview, 111., a corporation of Illinois Application May 18, 1955, Serial No. 509,300

8 Claims. (Cl. 121-45) This invention relates to hydraulic valves and especially to hydraulic control valve mechanism particularly useful in surface grinding machines and other machine tools, for controlling the limits of movement of a reciprocating Work-carrying carriage.

In hydraulically operated work-carrying carriages of the reciprocating type, it is customary to control the hydraulic motor'which drives the carriage by a direction control valve which includes a pilot valve mounted adjacent to the carriage of the machine tool and which is actuated by a pair of stop dogs extending from the carriage. The stop dogsare positioned to actuate the pilot valve when the carriage has reached the desired extreme positions of movement thereof. The pilot valve in turn controls a fluid direction control valve which feeds hydraulic fluid to one or the other end of the piston cylinder of a hydraulic motor driving the carriage.

It is one of the objects of this invention to provide valve mechanism of the above type wherein a manually operable shut-oil valve, a pilot valve to be operated by the actuating members carried by the carriage, and a fluid direction control valve are compactly and efiiciently arranged within bores formed in a single valve body.

It is another object of this invention to provide hydraulic valve mechanism as above described wherein the shut-off valve is provided with hydraulic fluid by-pass passages for by-passing hydraulic fluid from the pilot valve and from the direction control valve when the shut-oil valve isin its closed position.

It is a still further object of this invention to provide hydraulic control valve mechanism which includes a rotatable pilot valve which has an external annular recess and associated circumferentially spaced axial recesses which, in respective angular positions thereof, selectively direct hydraulic fluid to one of two ports leading respectively to the opposite endsof a four way direction control valve, and which further includes an axial fluid return bore and a pair of circumferentially spaced transverse bores which in said two angular positions of the pilot valve respectively open onto said two valve body ports, whereby a relatively small pilot valve controls both the feeding and returning of fluid to the opposite ends of the fluid direction control valve.

It is a still further object of this invention to provide hydraulic control valve mechanism as above described wherein there is'a cushion adjustment which adjusts the velocity of movement ofthe direction-control valve by varying the cross section of a portion of the hydraulic line extending from one of the ends of the directioncontrol valve cylinder bore and the pilot valve bore.

These and other objects of this invention will become apparent upon reference to the accompanying specification and the drawings showing a preferred embodiment of the invention.

In the drawings:

Fig. l is a fragmentary perspective view of the front of a portion of a reciprocating carriage of a grinding ma- Patented Sept. 16, 1958 ice which incorporates the valve mechanism of the invention;

Fig. 3 is an enlarged top View of the hydraulic control mechanism shown in Fig. 1;

Fig. 4 is a fragmentary bottom View of the apparatus of Fig. 3;

Fig. 5 is a longitudinal vertical section, taken along section line '5-5 of Fig. 3;

Fig. 6 is a horizontal section taken along section line 6-6 in Fig. 5;

Fig. 7 is a transverse section taken along section line 7-7 in Fig. 6;

Fig. 8 is a transverse section taken along section line 88 in Fig. 6;

Fig. 9 is a transverse section taken along section line 9-9 in Fig. 6;

Fig. 10 is a longitudinal vertical section taken along section line 10-10 in Fig. 8; v

Fig. 11 is an elevational view, partially broken away, to show the discharge passages within the valve body;

Fig. 12 is an elevational view of the shut-oil valve spool;

Fig. spool;

Fig. 14 is a transverse sectiontakenalong section line 14-14 in Fig. 13; t

Fig. 15 is a longitudinal section taken along section line 1515 in Fig. 14; and

Fig. 16 is a longitudinal section taken along section line 1616 in Fig. 14.

Reference should now be made to the drawings where like reference numerals indicate like elements throughout.

In Fig. l, a valve assembly 1 constructed in accordance with the invention is shown mounted on a stationary portion 2 of a machine tool opposite a reciprocable carriage 3, in this instance being the carriage of a grinding machine. The valve assembly 1 forms acompact, integral assembly containing all of the valve apparatus necessary to control the operation of a hydraulic motor which drives the carriage 3. This valve assembly includes a shut-off valve controlled by acon'trol handle 6, and a pilot'valve' controlled by a' valve'head 7 from which extends a pair of spaced extensions 8 and 9 which are respectively actuated by valve actuating stop dogs 11 and 12 secured to and reciprocating with the carriage 3. When the handle 6 is in its on or open position, and the carriage 3 reaches its extreme desired right hand position, the left stop dog 11 actuates the left pilot valve head extension 8 to rotate the pilot valve in' a direction clockwise as seen in Fig. 3. This initiates movement of a direction control valve, to be described, which reverses the direction of movement of the carriage 3 by controlling the movement of a piston of the hydraulic motor driving the carriage. When the carriage 3 reaches its farthest desired left hand extreme position, the right stop dog'lZ actuates the right pilot valve'head extension 9 to rotate the pilot valve in a counter-clockwise direction to effect movement of the carriage to the right. I

Refer now to the diagrammatic view of Fig. 2 which illustrates the entire hydraulic system for operating the hydraulic motor which drives the carriage 3. The portion of the figure enclosed within the dotted lines represents the valve assembly 1 shown in Fig. 1. Associated with the valve assembly is a tank 15 which contains a source of hydraulic fluid, such as oil, for operating the carriage hydraulic motor, diagrammatically indicated by the'box 17. An external feed conduit L leads from the tank 15 toa pump 18 which connects with the input port of the valve body of the valve assembly 1 via an external feed conduit L An input passage/a in the valve body inter:

13 is an elevational view of a pilot control valve connects the input port with a rotatable shut-off valve spool 19. The spool 19 has a through bore 21 which in the open position of the valve directs fluid received from the input passage a to a passage b in the valve body leading to a four-way direction control valve spool 26 slidably disposedwithin a bore 23. Fluid leaving the through bore 21 of the shut-off valve spool 19 also flows through a passage g leading to a pilot valve spool 25.

When the shut-off valve spool 19 is in its closed position, the input passage a opens onto an elongated external recess 28 formed in the shut-elf valve spool 19 which by- .passes hydraulic fluid around the pilot valve spool 25 and the direction control valve spool 26 through a passage k and a passage e' leading to an external discharge conduit L which empties into the tank 15.

The four-way direction control valve spool 26 has two axially spaced peripheral recesses 24a and 24b formed therein. When the spool 26 is in its left hand position, the fluid flowing in the passage b flows through the right hand annular space 24b of the spool and into a passage terminating in an external work circuit connecting port. The latter port connects with an external conduit L connecting with the right hand end of a piston cylinder of the hydraulic motor 17. This drives the carriage 3 to the left. The fluid which previously filled the left hand end of the hydraulic motor cylinder is forced into the external conduit L leading to another work circuit connecting port in the valve body of the valve assembly 1. The fluid then flows through a passage d within the valve body leading to the left hand peripheral recess 24a of the direction control valve spool 26, whereupon it passes through the recess 24a into discharge passages e and e. The fluid then emerges from an external fluid discharge port in the valve body and returns to the tank 15 through the external conduit L When the direction control valve spool 26 is in its right hand position, the fluid in the passage 1) flows into the left hand end of the hydraulic motor cylinder through the left hand peripheral recess 24:: of the spool, and the passage at leading to the external conduit L connecting with the left hand end of the hydraulic motor cylinder. The fluid which is then forced out of the right hand end of the hydraulic motor cylinder flows through the external conduit L into the valve body passage c connecting with the right hand peripheral recess 24b of the direction control valve spool 26. The fluid then flows into discharge passages h and e leading to the external return conduit L The position of the direction control valve spool is controlled by the pilot valve spool 25. Hydraulic fluid flows thereto through the aforementioned passage into a peripheral annular recess 27 formed in the pilot valve spool. When the pilot valve spool has been moved into its right or clockwise position by the left stop dog 11 of the carriage, an external axial recess 29 joining the annular recess 27 in the pilot valve spool periphery carries hydraulic fluid into a valve body passage g leading to the right hand end of the direction control valve bore 23, which actuates the direction control valve spool 26 to its extreme left hand position. Once the spool 26 has reached the last-mentioned position, the flow of hydraulic fluid through the passages f and g ceases. A cushion adjustment screw 30 is extendable within the passage g to vary the velocity of fluid flow within the passage g.

During the movement of the direction control valve spool 26 to the left, hydraulic fluid is forced out of the left hand end of the direction control valve through a passage i which communicates with a radial bore 32 formed in the pilot valve spool 25. The hydraulic fluid then flows into an axial discharge bore 34 in the pilot valve spool where it emerges in a return passage which joins the previously mentioned return passage e leading to the external tank return conduit L When the carriage 3 reaches its farthest left hand desired position, the right hand carriage stop dog 12 engages with the right hand pilot valve head extension 9, as above explained, to rotate the pilot valve spool 25 counter-clockwise as viewed from the top thereof. This brings an external axial recess 36 of the pilot valve spool opposite the port of the passage 1' leading to the left end of the direction control valve. The recess 36 opens onto the annular valve spool recess 27 so that hydraulic fluid flows from the passageway f in the valve body, through valve recesses 27 and 36 in the valve spool 25, and then into the passage 1, to carry hydraulic fluid to the left hand end of the direction control valve spool 26, moving the direction control valve spool to the right. Hydraulic fluid is forced out of the right hand end of the direction control valve bore 23 through the passage g and into a radial bore 40 formed in the pilot valve spool 25, which bore leads to the axial discharge bore 34 therein.

Refer now more particularly to Figs. 3 through 11 which show the detailed construction of the hydraulic control assembly 1. This apparatus includes the valve body 42 having a flat bottom surface 44, a flat left hand side surface 46, as viewed in Figs. 3 and 10, a flat top surface 47 merging through a gradually rounded surface 48 with a flat front surface 50. The right hand side of the valve body, as viewed in Figs. 3, 5, 6 and 10, has a protuberant portion 51 provided with a generally flat right side surface 52.

The valve body 42 is formed with three large valve bores 23, 56 and 57, which respectively receive the valve spools 26, 19 and 25. The direction control valve spool receiving bore 23 is a horizontal cylindrical bore extending from the upper, forward portion of the left hand side surface 46 of the valve body and terminating within the valve body adjacent to the right hand end thereof. As shown in Fig. 10, the bore 23 has slightly enlarged end portions 53 and 54. Extending vertically from the top surface 47 of the valve body to the rear of the direction control valve bore 23 are the spaced apart, parallel bores 56 and 57 which respectively rotatably receive the aforementioned shut-off valve spool 19 and the pilot valve spool 25, as clearly illustrated in Fig. 5. The bores 56 and 57 have reduced bottom portions 60 and 61, respectively, and the valve spools 19 and 25 are seated on shoulders immediately above these bore portions.

The top surface 47 of the valve body has a recess 63 formed therein which receives a valve top plate 64 which is flush with the top of the valve body. The valve top plate 64 has holes centered with respect to the vertical valve bores 56 and 57, which holes receive the necks 66 and 68, respectively, of the valve spools 19 and 25. Secured to the valve spool necks 66 and 68 are the valve spool heads 70 and 7. The control handle 6 for rotating the shut-off valve spool is secured to the spool head 70. Stop pins 7272 extend upwardly from the valve top plate 64. These pins are respectively engaged by a pin 74 projecting from the shut-off valve head 70 when the shut-ofl? valve is respectively in its open and closed po sitions. The pin 74 performs an additional function of 'keying the shut-off valve head 70 to the shut-off valve neck 66.

Secured to the left hand side surface 46 of the valve body is an end cap assembly comprising a valve cap gasket 75 which closes off the open end of the direction control valve bore 23 and a valve cap 76 which is pressed against the valve cap gasket 75 to provide a fluid-tight seal by bolts 73 threading into the valve body.

The valve body and valve cap together are provided with four vertical tapped holes in the bottom thereof for making external connection to the external feed and dis charge conduits L and L (see Fig. 2), and with the conduits L and L leading to the hydraulic motor 17. Three of these tapped holes 77, 78 and 79 (see Fig. 4) are formed in the valve body 42. The tapped hole 77 provides an external fluid feed port, the tapped hole 78 defines a fluid return port for connection with the externalduit L leading to the right end of the carriage motor cylinder. The valve cap 76 has a. tapped hole. 80 formed in the bottom thereof. The hole 80 defines a work circuit. connecting port which connects with the external conduit L leading to the left end of the" carriage motor cylinder.

The various internal passages within the main valve body which'interconnect the various external main valve body ports and valve bores are formed by bores drilled from the outside of the valve body which intersect with the various tapped holes and valve bores above mentioned, and which are plugged to close off the ends of these holes. The'passage a which leadsfrom the hydraulic fluid input port to the shut-01f valve bore 56 is completed by drilling a bore 81 (Fig. 5) in the right side surface 52 of the valve body, which bore intersects with the vertical feed hole 77 and the shut-off valve bore 56 and terminates midway through the wall between the valve spool bores 56 and 57. The end of the bore 81 is closed 011 by a plug-82.

When the shut-off valve spool 19 is rotated into its open position, the through bore 21' thereof makes registry with the valve body bore 81. The passage f leading from the shut-off valve bore 56 to the pilot valve bore 57' is formed by drilling a bore 83 in axial alignment with the bore 81.

The passage bbetween the shut-off valve bore 56 and the direction control valve bore 23 is formed by drilling a bore 85 (Fig. 8) at an angle through the rear wall of the valve body and which intersects the portion of the bore 81 extending slightly beyond the shut-off valve bore and also intersects the direction control valve bore 23 forming the port 86 in the medial region of the direction control valve bore 23. The outer end of the bore 85 is closed by a plug 87.

The port 86 opens onto the right hand peripheral recess 24b of the direction control valve spool 26 whenthe latter is initsextreme left hand position, and it opens onto the left hand peripheral recess 24a of the spool 26 when the latter is in its right hand position.

The passage leading from the direction control valve bore 23 to the work circuit connecting port defined by the vertical hole 79 is formed in part by drilling a longitudinal bore 88 (Fig. 10) in. the right surface 52 of the valve body, which. bore intersects. the vertical tapped hole 79. A plug 88' closes oif the bore 88. A port opening89 whichinterconnects the bore 88 with the direction. control valve bore 23 is formed by a bore 90 (Fig. 8) drilled at an angle through the bottom of themain valve body and.

which intersects both the bore 88 and the direction controlvalve bore 23 to the right of the input port 86 in the medial portion of the direction control valve bore. The port opening 89 communicates with the annular-space 24b of the direction control valve spool in all positions of the latter. The bore 90 is closed by a plug 91'.

Theinternal passage 0. extending between the external conduit L leading to the left end of the carriage motor cylinder, and the direction control valve bore 23 is partially completed through the valve body by a longitudinal bore 92 (Fig. which is drilled part way through the main valve body from the left surface 46 thereof. The bore 92 is in alignment with the aforementioned bore 88 and joins the direction control valve bore 23 through a bore' 93 (Fig; 6) drilled through the bottom of the valve body: at the same angle as the aforementioned bore 90 so as to intersect both the longitudinal bore 92 and the direction control'valv'e bore 23. A port 94 is formed in the walls of the direction control valve bore 23 to the left of the medial input port 86 thereof. The port94 opens onto the left hand peripheral recess 24a of the direction control valve spool, for all positions of the latter. The bore 93 is closed by a plug 93' (Fig. 4).

It is apparent more particularly from Fig. 6 that hydraulic fluid entering the direction control valve bore 23 through the input port 86 respectively flows through the peripheral recess. 24b of the spool 26 into the longitudinal bores 88 and 92 through the direction control valve bore ports 89 and 94' when the direction control valve spool is respectively in its fully left hand and fully right hand positions. When one of the bores 88 or 92 functions as a feed bore leading to one end of the carriage motor cylinder, then the other of these two bores acts as a return passage for fluid forced out of the other end of the carriage motor cylinder, as above explained.

Connection between the vetrical tapped hole in the valve cap 76 and the valve body bore 92 is made through a longitudinal bore 94 (Fig. 10) drilled through the'valve cap 76 and which intersects the vertical tapped hole 80. The bore 94 is in registry with the main valve body bore 92 and a corresponding hole formed in the valve cap gasket 75. The end of the bore 94 is closed by a plug 95.

The discharge passages e and h leading from the direction control valve bore 23 (Fig. 2) are respectively formed by the bores 96 and 97 (Fig. 11) drilled through the bottom of the main valve body and intersecting the direction control valve bore 23 forming ports 100 and 101 respectively to the left and to the right of the ports 93 and 89. The ports 100 and 101 are positioned so as to be respectively in communication with the peripheral direction conrol valve recesses 24!; and 245 when the spool 26 is respectively in its left andright extreme positions. The longitudinal bore 98 (Fig. 11) drilled through the right side surface face 52 of the valve body intersects the bores 96 and 97 and forms most of the main discharge passage e. The outer ends of the bores 96, 97 and 98 are respectivelyclosed off by plugs 102, 104 and 106. The longitudinal bore 98 intersects with the vertical tapped hole 78 in the bottom of the main valve-body to complete the internal passage e. The tapped hole 78 connects with the external discharge conduit L leading'to the storage tank 15.

As previously explained, the pilot valve spool 25 controls the positioning of the direction control valve spool 26. The interconnection between the pilot valve bore 57 and the direction control-valve bore 23 is obtained in part through a horizontally extending bore 106 (Fig. 6) drilled from the left hand end of the main valve body by a drill spindle extending at an angle through the left end of the direction control valve bore 23. The opening is continued through the wall at the opposite end of the pilot valve bore 57 and thus two aligned ports 109 and 110 are formed in the walls of the pilot valve bore 57. Connection with the extension of the bore 106 at said opposite end of the pilot valve bore 57 is effected by a longitudinal bore 112 drilled through the right side of the valve body. The open end of the bore 112 is counterbored at 114 to receive part of a cushion adjustment assembly 116 including the adjustment screw 38. The screw 39 has a tapered tip 118, a screw threaded intermediate shank portion 120 threaded into the portion of the valve body bore 112, axially spaced unthreaded enlarged collar portions 121 and 122 between which a compressed sealing gasket ring 123 is interposed, and a screw threaded outer end portion 124 having a screw driver slot in the end face. The threaded outer end portion 124 threadedly receives a locking nut 126 thereover. the sealing ring 123 are disposed within the counterbore 114 of the longitudinal bore 112.

Interconnection between the bore 112 and the right hand end of the direction control valve bore 23 is effected by a transverse bore 127 drilled through the rear of the valve body and intersecting the longitudinal bore 112 and the enlarged right portion 54 of the direction control valve bore 23. Thetransverse bore 127 is closed."

The collar portions 121 and 122 together with off by a plug 129. The bores 112 and 127 thus complete the internal passage g leading between the pilot valve bore 57 and the direction control valve bore 23.

Adjustment of the velocity of fluid flow between the last two mentioned bores is controlled by the positioning of the tapered tip 118 of the adjustment screw 30. By threading the screw into or out of the threaded portion 115 of the longitudinal bore 112, the tapered tip 118 of the adjusting screw impedes to a varying degree the flow of hydraulic fluid between the bores 112 and 127.

When the pilot valve spool 25 is in the right hand position shown in Fig. 3, the axial recess 29 thereof .connecting with the peripheral annular recess 27, and the radial bore 32 thereof are respectively opposite the pilot valve bore ports 110 and M9 so that hydraulic fluid is directed through the peripheral annular recess 27 and into the port 110 leading to the right hand end of the direction control valve bore 23, and the hydraulic fluid returning from the left hand end of the direction flow valve bore 23 enters the pilot valve spool through the port 109, passing through the radial bore 32 and down the axial discharge bore 34 thereof to the bottom portion 61 of the pilot valve spool bore 57. The connection between the bottom bore portion 61 and the discharge bore 98 is effected by means of a bore 131 (Fig. 9) drilled through the front of the valve body and intersecting the discharge bore 98, and the bottom of the pilot valve bore. The openend of the bore 131 is closed by a plug 132.

When the right hand stop dog 12 actuates the pilot valve spool to its left hand position (not shown), the pilot valve bore ports 110 and 109 are respectively in register with the radial pilot valve spool bore 40 and the axial pilot valve recess 36. In the last-mentioned position of the pilot valve spool, hydraulic fluid entering the annular peripheral recess 27 of the pilot valve spool reaches the left hand end of the direction control valve bore 23 via the axial pilot valve spool recess 36 and the valve body bore 106. Fluid returning from the right hand end of the direction control valve bore enters the axial discharge bore 34 of the pilot valve spool through the pilot valve spool port 110 and the radial bore 40 of the pilot valve spool. When the shut-off spool 19 is rotated to its extreme clockwise position, which is the closed or 011 position thereof, the through bore 21 thereof is rotated out of registry with the longitudinal bore 81 leading to the shut-off valve bore 56. The shut-off valve spool has a pair of vertical external recesses 28-48 (see Fig. 7) on opposite sides of the spool. These vertical recesses open onto a cylindrical space 134 formed in the bottom of the shut-01f valve spool. When the shut-off spool is in the closed position, one of the recesses 28 is brought into registry with the longitudinal input bore 81 in the valve body and hydraulic fluid is by-passed around the pilot valve spool and the direction control valve spool through a path including one of the vertical recesses 28,

the valve spool space 134, the reduced bottom portion 61) of the shut-off valve bore, and a bore 138 drilled through the front of the valve body and intersecting the discharge bore 98 and the bottom of the shut-01f valve spool bore 56, The open end of the bore 138 is closed oil by a plug 139.

The present invention has thus provided a compact direction control valve assembly wherein a shut-01f valve spool, a direction control valve spool and a pilot valve spool are compactly assembled within a main valve body having various bores and internal passageways formed by drilling or boring openings through the outer surface of the main valve body.

In compliance with the requirements of the patent statutes I have here shown and described a preferred embodiment of my invention. It is, however, to be understood that the invention is not limited to the precise construction here shown, the same being merely illustrative and desire to secure by Letters Patent is:

1. A directional control valve assembly of the reversing valve type for use in a hydraulic power transmission system comprising: a valve body having a first pair of external work circuit connecting ports adapted to be connected with opposite ends of a hydraulic cylinder and a second pair of external ports constituting a hydraulic fluid input port and a hydraulic fluid output port, respectively; said body also having a shut-off valve bore and a pilot valve bore having respective parallel longitudinal axes spaced from one another and opening on to the same outer face of the valve body, and a direction control valve bore opposite said other two bores and having a longitudinal axis at right angles to and otfset from said parallel axes and opening in an end of the valve body; said valve body also having internal passages formed therein comprising: a first passage interconnecting said fluid input port and said shut-off valve bore, a second passage interconnecting said shut-off valve bore and said pilot valve bore, a third passage interconnecting said second passage with an intermediate portion of said direction control valve bore, a fourth passage interconnecting said pilot valve bore with one end of said direction control valve bore and in line with the opening of the direction control valve at the end of the valve body, a fifth passage interconnecting said pilot valve bore with the other end of said direction control valve bore and a cushion adiusb ing means therein for adjusting the size of a portion of said latter passage, a sixth and seventh passage respectively interconnecting spaced intermediate portions of said direction control valve bore respectively with said work circuit ports, an eighth passage interconnecting said shut-ofi valve bore with said discharge port, a ninth passage interconnecting said pilot valve bore with said discharge port, and fluid return passage means interconnecting said direction control valve bore with said fluid discharge port; a manually operable shut-ofl? valve rotatably mounted in said shut-off bore for interconnecting said first and second passages when turned to one angular position and for interconnecting said first and eighth passages when turned to another angular position; a fluid direction control valve mounted for longitudinal movement in said direction control valve bore for interconnecting said third and seventh passages and said sixth passage and fluid return passage means, respectively, in one extreme position thereof, and for interconnecting said third and sixth passages and said seventh passage and fluid return passage means, respectively, in the other extreme position thereof; and a pilot valve adapted to be operated by a pair of stop dogs on a machine tool carriage and rotatably mounted in said pilot valve bore for interconnecting said second and fifth passages and said fourth and ninth passages, respectively, when said pilot valve spool is operated into one angular position by one of the carriage stop dogs, and for interconnecting said second and fourth passages and said fifth and ninth passages, respectively, when said pilot valve spool is operated into another angular position bythe other carriage stop dog.

2. A directional control valve assembly of the reversing valve type for use in a hydraulic power transmission system comprising: a valve body having a first pair of external work circuit connecting ports adapted to be connected with opposite ends of a hydraulic cylinder and a second pair of external ports constituting a hydraulic fluid input port and a hydraulic fluid output port, respectively; said body also having a shut-off valve bore and a pilot valve bore having respective parallel longitudinal axes, and a direction control valve bore opposite said other two bores and having a longitudinal axis at right angles to said parallel axes; said valve body also having internal passages formed therein comprising: a first passage interconnecting said fluid input port and said shut-01f valve bore, a second passage interconnecting said shut-01f valve bore and said pilot valve bore, a third passage intercon- 9 necting said second passage with said direction control valve bore, a fourth passage interconnecting said pilot valve bore with one end of said direction control valve bore, a fifth passage interconnecting said pilot valve bore with the other end of said direction control valve bore, a sixth and a seventh passage respectively interconnecting portions of said direction control valve bore respectively with said work circuit ports, an eighth passage interconnecting said shut-off valve bore with said discharge port, a ninth passage interconnecting said pilot valve bore with said discharge port, and fluid return passage means interconnecting said direction control valve bore with said fluid discharge port; a manually operable shut-ofi valve rotatably mounted in said shut-off bore for interconnecting said first and second passages when turned to one angular position and for interconnecting said first and eighth passages when turned to another angular position;

a fluid direction control valve mounted for longitudinal movement in said direction control valve bore for interconnecting said third and seventh passages and said sixth passage and fluid return passage means, respectively, in one extreme position thereof, and for interconnecting said third and sixth passages and said seventh passage and fluid return passage means, respectively, in the other extreme position thereof; and a pilot valve adapted to be operated by a pair of stop dogs on a machine tool carriage and rotatably mounted in said pilot valve bore for interconnecting said second and fifth passages and said fourth and ninth passages, respectively, when said pilot valve spool is operated into one angular position by one of the carriage stop dogs, and for interconnecting said second and fourth passages and said fifth and ninth passages, respectively, when said pilot valve spool is operated into another angular position by the other carriage stop dog.

3. A directional control valve assembly of the reversing valve type for use in a hydraulic power transmission system comprising: a valve body having a first pair of external work circuit connecting ports adapted to be connected with opposite ends of a hydraulic cylinder and a second pair of external ports constituting a hydraulic fluid input port and a hydraulic fluid output port, respectively; said body also having a shut-ofi valve bore and a pilot valve bore, and a direction control valve bore; said valve body also having internal passages formed therein comprising: a first passage interconnecting said fluid input port and said shut-off valve bore, a second passage interconnecting said shut-ofl valve bore and said pilot valve bore, a third passage interconnecting said second passage with said direction control valve bore, a fourth passage interconnecting said pilot valve bore with one end of said direction control valve bore, a fifth passage interconnecting said pilot valve bore with the other end of said direction control valve bore and a cushion adjusting means therein for adjusting the size of a portion of said latter passage, a sixth and a seventh passage respectively interconnecting portions of said direction control valve bore respectively with said work circuit ports, an eighth passage interconnecting said shut-off valve bore with said discharge port, a ninth passage interconnecting said pilot valve bore with said discharge port, and fluid return passage means interconnecting said direction control valve bore with said fluid discharge port; a manually operable shutoff valve rotatably mounted in said shut-off bore for interconnecting said first and second passages when turned to one angular position and for intercon necting said first and eighth passages when turned to another angular position; a fluid direction control valve mounted for longitudinal movement in said direction control valve bore for interconnecting said third and seventh passages and said sixth passage and fluid return passage means, respectively, in one extreme position thereof, and for interconnecting said third and sixth passages and said seventh and fluid return passage means, respectively, in the other extreme position thereof; and a pilot valve It) adapted to be operated by a pair of stop dogs on a machine tool carriageand rotatably mounted in said pilot valve bore for intercom 'iecting said second and fifth passages and said fourth and ninth passages, respectively,v

when said pilot valve spool is operated into one angular position by one of the carriage stop dogs, and for interconnecting said second and fourth passages and said fifth and ninth passages, respectively, when said pilot valve spool is operated into another angular position by the other carriage stop'dog.

4. A directional control valve assembly of the reversing valve type for use in a hydraulic power transmission system comprising: means providing a first pair of external Work circuit connecting ports adapted to be connected with opposite ends of a hydraulic cylinder, a second pair of external ports constituting a hydraulic fluid input port and a hydraulic fluid output port, respectively, a shut-off valve bore, a pilot valve bore, a direction control valve bore, a first passage interconnecting said fluid input port and said shut-ofl valve bore, a second passage interconnecting said shut-off valve bore and said pilot valve bore, a third passage interconnecting said second passage with said direction control valve bore, a fourth passage interconnecting said pilot valve bore with one end of said direction control valve bore, a fifth passage interconnecting said pilot valve bore with the other end of said direction control valve bore and a cushion adjusting means therein for adjusting the size of a portion of said latter passage, a sixth and a seventh passage respectively interconnecting spaced intermediate portions of said direction control valve bore respectively with said work circuit ports, an eighth passage interconnecting said shut-oft" valve bore with said discharge port, a ninth passage interconnecting said pilot valve bore with said discharge port, and fluid return passage means interconnecting said direction control valve bore with said fluid discharge port; a manually operable shutoff valve rotatably mounted in said shut-off bore for interconnecting said first and second passages when turned to one angular position and for interconnecting said first and eighth passages when turned to another angular position; a fluid direction control valve mounted for longitudinal movement in said direction control valve bore for interconnecting said third and seventh passages and said sixth passage and fluid return passage means, respectively, in one extreme position thereof, and for interconnecting said third and sixth passages and said seventh passage and fluid return passage means, respectively, in the other extreme position thereof; and a pilot valve adapted to be operated by a pair of stop dogs on a machine tool carriage and rotatably mounted in said pilot valve bore for interconnecting said second and fifth passages and said fourth and ninth passages, respectively; when said pilot valve spool is operated into one angular position by one of the carriage stop dogs, and for interconnecting said second and fourthpassages and said fifth and ninth passages, respectively, when said pilot valve spool is operated into another angular position by the other carriage stop dog.

5. A directional control valve assembly of the reversing valve type for use in a hydraulic power transmission system comprising: a valve body having means providing a first pair of external work circuit connecting ports adapted to be connected with opposite ends of a hydraulic cylinder, a second pair of external ports constituting a hydraulic fluid input port and a hydraulic fluid output port, respectively, a shut-01f valve bore, a pilot valve bore parallel to the shut-ofi valve bore, a direction control valve bore at right angles to the other two and with its longitudinal axis spaced from the longitudinal axes of the other bores and opening at an end of the valve body, a first passage interconnecting said fluid input port and said shut-off valve bore, a second passage interconnecting said shut-off valve bore and said pilot valve bore, a third passage interconnecting said second passage with said 1 1 direction control valve bore, a fourth passage interconnecting said pilot valve bore with one end of said direction control valve bore, a fifth passage interconnecting said pilot valve bore with the other end of said direction control valve bore, a sixth and a seventh passage respectively interconnecting spaced intermediate portions of said direction control valve bore respectively with said work circuit ports, an eighth passage interconnecting said shut-off valve bore with said discharge port, a ninth passage interconnecting said pilot valve bore with said discharge port, and fluid return passage means interconnecting said direction control valve bore with said fluid discharge port; a manually operable shut-off valve rotat ably mounted in said shut-off bore for interconnecting said first and second passages when turned to one angular position and for interconnecting said first and eighth passages when turned to another angular position; a fluid direction control valve mounted for longitudinal movement in said direction control valve bore for interconnecting said third and seventh passages and said sixth passage andfluid return passage means, respectively, in one extreme position thereof, and for interconnecting said third and sixth passages and said seventh passage and fluid return passage means, respectively, in the other extreme position thereof; and a cylindrical pilot valve rotatably mounted within said pilot valve bore and having an axial fluid discharge passage opening onto one end thereof and a pair of transverse bores communicating with said axial fluid discharge passage and opening onto two circumferentially spaced points on the outer surface of the valve, an annular external fluid feed recess in said pilot valve and a pair of circumferentially spaced external axially extending connecting recesses communicating with said anular feed recess, in one angular position of said pilot valve one of said transverse bores thereof and one of said connecting recesses thereof opening respectively onto the adjacent ports of said fourth and fifth passages to direct fluid respectively from one end of said direction control valve bore to said pilot valve discharge passage and to direct fluid from said annular pilot valve feed recess to the other end of said direction control valve bore, to move the direction control valve to one extreme position, in another angular positionof said pilot valve the other of said transverse pilot valve bores thereof and the other of said axial connecting recesses thereof re spectively opening onto the adjacent ports of said fifth and fourth passages to respectively direct fluid from said other end of said direction control valve bore to said pilot valve discharge passage, and to direct fluid from said annular pilot valve feed recess of said valve to said one end of said control valve bore, to move said direction control valve to its other extreme position, said annular pilot valve feed recess opening onto the adjacent port of said second passage in said two angular positions of said pilot valve to receive fluid from said shut-off valve bore, said axial fluid discharge passage of said pilot valve opening onto the adjacent port of said ninth passage in said two angular positions of said pilot valve to direct fluid to said external discharge port, and means for actuating said pilot valve to said two angular positions thereof.

6. A directional control valve assembly of the reversing valve type for use in a hydraulic power transmission system comprising: means providing a first pair of external work circuit connecting ports adapted to be connected with opposite ends of a hydraulic cylinder, a second pair of external ports constituting a hydraulic fluid input port and a hydraulic fluid output port, respectively, a shut-off valve bore, a pilot valve bore, a direction control valve bore, a first passage interconnecting said fluid input port and said shut-off valve bore, a second passage interconnecting said shut-off valve bore and said pilot valve bore, a third passage interconnecting said second passage with said direction control valve bore, a fourth passage interconnecting said pilot valve bore with one end of said direction control valve bore, a

passage means interconnecting said direction control valve bore with said fluid discharge port; a manually operable shut-off valve rotatably mounted in said shut-off bore for interconnecting said first and second passages when turned to one angular position and for interconnecting said first and eighth passages when turned to another angular position; a fluid direction control valve mounted for longitud nal movement in said direction control valve bore for interconnecting said third and seventh passages and said sixth passage and fluid return passage means, respectively, in one extreme position thereof, and for interconnecting said third and sixth passages and said seventh passage and fluid return passage means, respectively, in the other extreme position thereof; and a pilot valve rotatably mounted within said pilot valve bore and having a fluid discharge passage opening onto one end thereof and a pair of bores communicating with said fluid discharge passage and opening onto two circumferentially spaced points on the outer surface of the valve, an external fluid feed recess in said pilot valve and a pair of circumferentially spaced external connecting recesses communicating with said feed recess, in one angular position of said pilot valve one of said bores thereof and one of said connecting recesses thereof opening respectively onto the adjacent ports of said fourth and fifth passages to direct fluid respectively from one end of said direction control valve bore to said pilot valve discharge passage and to direct fluid from said pilot valve feed recess to the other end of said direction control valve bore, to move the direction control valve to one extreme position, in another angular position of said pilot valve the other of said pilot valve bores thereof and the other of said connecting recesses thereof respectively opening onto the adjacent ports of said fifth and fourth passages to respectively direct fluid from said other end of said direction control valve bore to said pilot valve discharge passage, and to direct fluid from said pilot valve feed recess of said valve to said one end of said control valve bore, to move said direction control valve to its other extreme position, said pilot valve feed recess opening onto the adjacent port of said second passage in said two angular positions of said pilot valve to receive fluid from said shut-off valve bore, said fluid discharge passage of said pilot valve opening onto the adjacent port of said ninth passage in said two angular positions of said pilot valve to direct fluid to said external discharge port, and means for actuating said pilot valve to said two angular positions thereof.

7. A directional control valve assembly of the reversing valve type for use in a hydraulic power transmission system comprising: means providing a first pair of external work circuit connecting ports adapted to be connected with opposite ends of a hydraulic cylinder, a second pair of external ports constituting a hydraulic fluid input port and a hydraulic fluid output port, respectively, a shutoff valve bore, a pilot valve bore, a direction control valve bore, a first passage interconnecting said fluid input port and said shut-off valve bore, a second passage interconnecting said shut-off valve bore and said pilot valve bore, a third passage interconnecting said second passage with said direction control valve bore, a fourth passage interconnecting said pilot valve bore with one end of said direction control valve bore, a fifth passage interconnecting said pilot valve bore with the other end of said direction control valve bore, a sixth and a seventh passage respectively interconnecting spaced intermediate portions of said direction control valve bore respectively with said work circuit ports, an eighth passage interconnecting said shut-off valve bore with said discharge port, a ninth passage interconnecting said pilot valve bore with said discharge port, and fluid return passage means interconnecting said direction control valve bore with said fluid discharge port; a cyclindrical shut-off valve rotatably mounted in said shut-ofi valve bore and having a through bore extending at a substantial angle to the axis of rotation of the shut-off valve, said through bore communicating simultaneously with the adjacent ports of said first and second passage when the shut-off valve is in its open position, whereby liquid is directed to said pilot valve bore and said direction control valve bore from said input port through said shut-off valve, said shut-off valve also having an axial external recess circumferentially spaced from said through bore therein and communicating simultaneously with the adjacent ports of said first and eighth passages when the shut-01f valve is in its closed position to by-pass hydraulic fluid around said pilot and direction control valve bores, and means for rotating said shut-off valve between said open and closed positions; a fluid direction control valve mounted for longitudinal movement in said direction control valve bore for interconnecting said third and seventh passages and said sixth passage and fluid return passage means, respectively, in one extreme position thereof, and for interconnecting said third and sixth passages and said seventh passage and fluid return passage means, respectively, in the other extreme position thereof; and a pilot valve adapted to be operated by a pair of stop dogs on a machine tool carriage and rotatably mounted in said pilot valve bore for interconnecting said second and fifth passages and said fourth and ninth passages, respectively, when said pilot valve spool is operated into one angular position by one of the carriage stop dogs, and for interconnecting said second and fourth passages and said fifth and ninth passages, respectively, when said pilot valve spool is operated into another angular position by the other carriage stop dog.

8. A directional control valve assembly of the reversing valve type for use in a hydraulic power transmission system comprising: means providing a first pair of external work circuit connecting ports adapted to be con nected with opposite ends of a hydraulic cylinder, a second pair of external ports constituting a hydraulic fluid input port and a hydraulic fluid output port, respectively, a shut-01f valve bore, a pilot valve bore, a direction control valve bore, a first passage interconnecting said fluid input port and said shut-off valve bore, a second passage interconnecting said shut-ofi valve bore and said pilot valve bore, a third passage interconnecting said second passage with said direction control valve bore, a fourth passage interconnecting said pilot valve bore with one end of said direction control valve bore, a fifth passage interconecting said pilot valve bore with the other end of said direction control valve bore, a sixth and a seventh passage respectively interconnecting spaced intermediate portions of said direction control valve bore respectively with said work circuit ports, an eighth passage interconnecting said shut-off valve bore with said discharge port, a ninth passage interconnecting said pilot valve bore with said discharge port, and fluid return passage means interconnecting said direction control valve bore with said fluid discharge port; a shut-01f valve rotatably mounted in said shut-off valve bore and having a through bore communicating simultaneously with the adjacent ports of said first and second passage when the shut-01f valve is in its open position, whereby liquid is directed to said pilot valve bore and said direction control valve bore from said input port through said shut-off valve,

said shut-off valve also having a recess circurnferentially spaced from said through bore therein and communicating simultaneously with the adjacent ports of said first and eighth passages when the shut-off valve is in its closed position to by-pass hydraulic fluid around said pilot and direction control valve bores, and means for rotating said shut-off valve between said open and closed positions; a fluid direction control valve mounted for longitudinal movement in said direction control valve bore for interconnecting said third and seventh passages and said sixth passage and fluid return passage means, respectively, in one extreme position thereof, and for interconnecting said third and sixth passages and said seventh passage and fluid return passage means, respectively, in the other extreme position thereof; and a pilot valve adapted to be operated by a pair of stop dogs on a machine tool carriage and rotatably mounted in said pilot valve bore for interconnecting said second and fifth passages and said fourth and ninth passages, respectively, when said pilot valve spool is operated into one angular position by one of the carriage stop dogs, and for interconnecting said second and fourth passages and said fifth and ninth passages, respectively, when said pilot valve spool is operated into another angular position by the other carriage stop dog.

References Cited in the file of this patent UNITED STATES PATENTS 309,099 Royce Dec. 9, 1884 1,931,452 Wheeler Oct. 17, 1933 1,946,348 Bath Feb. 6, 1934 2,108,354 Swanson Feb. 15, 1938 2,192,839 Orcutt Mar. 5, 1940 2,283,397 Tucker May 19, 1942 2,299,851 Schafer Oct. 27, 1942 2,432,305 Geiger Dec. 9, 1947 2,549,979 Lane Apr. 24, 1951 2,608,183 Osmond Aug. 26, 1952 FOREIGN PATENTS 113,696 Germany Oct. 4, 1900 342,463 Germany Oct. 18, 1921 UNITED STATES PATENT OFFICE CERTIFICATE @F CQRREGTTGN Patent No. 2,851,996 September 16, 1958 William So Bunnell It is hereby certified that error appears in the printed specification. of the above numbered patent requiring correction and that the said Letters Patent should read as corrected belowo Column 11, line 3, after 'bore" insert and intersecting the control valve bore opening at the end of the valve body s Signed and sealed this 18th day of November 1958.,

(SEAL) Attest:

KARL AXLINE ROBERT C.'--WATSON Attesting Officer Commissioner of Patents 

